To begin: To understand what another has done is both to have a particular sort of true description of the action he has performed, one that reveals it to be intentional, and to know the agent's practical reason for performing that action. In turn, to know an agent's reason for performing some particular action involves understanding his motivation in doing it. An interpreter cannot, though, really understand an agent's motivation in performing an action unless she sees that motivation as a motivation, unless she is cognizant of its force as a motivation. It is not enough, that is to say, to understand what a person who intentionally sips from a saucer of mud has done to note merely that he had the desire to sip from a saucer of mud, and believed himself both possessed of a saucer of mud and able to sip from it. An interpreter has also to comprehend what in desiring to sip from a saucer of mud was attractive to him. Now usually, of course, there is no problem in our comprehending what it is in the desires had by people around us that attracts them as desirable. The people around us are more or less like us in many if not most of their desires, wants and wishes, and few of them desire to sip from a saucer of mud, so in our day to day life we do not often have cause to turn our attention explicitly to the question from whence arrives the motivational force of their desires. Still, it is not exceedingly uncommon for us, even for those of us who are not psychologists, sociologists, or anthropologists, to be stumped by some piece of what we take to be behaviour. How are we to make sense of some such piece of strange behaviour? One way is to connect that piece of behaviour to one or more of the strange agent's self-regarding ends. If we can see in sipping from a saucer of mud a way of maintaining self-respect, or even a way to delight in the taste of mud, we can understand the desire the agent had to sip from a saucer of mud. We need not connect his self-regarding end to an intention to realize that end in or through his action; we need only, I think, connect it to an expectation of realizing it. But is this the only way we can make sense of desires we ourselves do not share and cannot, at first at least, imagine sharing? I think that it is. Without our perceiving a connection to an intention or an expectation of realizing some self-regarding end, we cannot see in any consideration we attribute to an agent a motivation to act. The motivating force of the consideration that spurred action will remain beyond our ken, the action stemming from it unfathomable and inexplicable.

Any motive to act must be my own. Your desire cannot motivate me; the actor must be able to perceive an internal motivation to act. A abstract ethical theory is impossible, as it can never develop any basis for motivation. Contractarianism best allows the development of ethical norms from egoism. GAUTHIER:

A contractarian theory of morals, developed as part of the theory of rational choice, has evident strengths. It enables us to demonstrate[s] the rationality of impartial constraints on the pursuit of individual interest to persons who may take no interest in others' interests. Morality is thus given a sure grounding in a weak and widely accepted conception of practical rationality. No alternative account of morality accomplishes this. Those who claim that moral principles are objects of rational choice in special circumstances fail to establish the rationality of actual compliance with these principles. Those who claim to establish the rationality of such compliance [and] appeal to a strong and controversial conception of reason that seems to incorporates[s] prior moral suppositions. No alternative account generates morals, as a rational constraint on choice and action from a non-moral, or morally neutral base.

[This framework originally and generously contributed by Torrey Pines VB.]